Ubuntu Christian Edition is an operating system
geared towards Christians. It is based on the
popular Ubuntu Linux and includes the best
available Christian software, such as GnomeSword,
a top of the line Bible study program, and several
additional modules. It also includes fully
integrated Web content parental controls powered
by Dansguardian and a graphical tool for adjusting
the parental control filter settings. If you are looking for a KDE-based distribution, consider Ichthux.

Slimux is a from-source, trimmed down distribution
of Linux created with the idea of keeping the base
system as slim as possible. The goal for Slimux
1.x.x is to have the base package less than 16M
while still maintaining the functionality of a
more typical system.

Seccheck is a feature rich, modular, host-level
security checker for Solaris 10. Easily expandable
with customised modules, Seccheck produces highly
detailed reports based around known and published
security best-practices and guidelines. It also
produces recommendations on how to fix flagged
security issues.

UNIXem is a small and simple library that provides emulation of several popular Unix API functions on the Win32 platform. Its primary purpose is to assist Win32 programmers who are porting to Unix or are writing multi-platform code. API functions include opendir/readdir/closedir, glob/globfree, readv/writev, pathconf/realpath, mmap/munmap/msync, dlopen/dlclose/dlsym/dlerror, gettimeofday, and getpagesize.

btfs can be used as /init for constructing a
run-time environment before running the real init.
It supports extracting compressed (*.cgz, *.cbz2)
and uncompressed (*.co) cpios located on a
compile-defined directory (/). Also, it creates a
tmpfs filesystem as the new root, if / isn't one
already and the purpose of the initramfs isn't for
starting a system in another location (disk,
network, etc.). That will allow for the data on /
to be swapped to disk when swap devices are
activated later.

myOS is a minimalistic, OpenGL capable, GNU/Linux-based system without X. It is a bare bones Linux system, stripped of everything but the files necessary to compile and run OpenGL/C code. It has a simplified directory structure and a cleaned-up internal cross referencing. It has two available variants. myOSx-less fits within a 64 MB RAM disk and features a WebKit based on Trolltech's Qtopia demo Web browser. myOSx is oriented for X11, and its development tools are built around Trolltech Qtopia to produce applications based on the WebKit and for the framebuffer of the original myOS system.

Partimage Is Not Ghost (PING) is a live Linux ISO
based on LFS (Linux From Scratch). It can be burnt on a CD and booted, or integrated in a PXE/RIS environment. Several tools that make it the perfect choice for easily backing up and restoring whole partitions are included. It supports backups to and from SMB shares, backup of BIOS data, the ability to blank the local admin's password, creation of bootable restoration DVDs, the ability to partition and format a disk before installing Windows, and more.

Nuttx is a real-time embedded operating system (RTOS). It has a small footprint that is usable in micro-controller environments. It is fully scalable from tiny (8-bit) to moderate embedded (32-bit) systems. It also aims to be fully compliant to standards, to be fully real time, and to be totally open.